Fix recursion accounting in XPath expressions:

  https://gitlab.gnome.org/GNOME/libxml2/-/issues/264

Taken from upstream:

  https://gitlab.gnome.org/GNOME/libxml2/-/commit/3e1aad4fe584747fd7d17cc7b2863a78e2d21a77

diff --git a/xpath.c b/xpath.c
--- a/xpath.c
+++ b/xpath.c
@@ -10983,7 +10983,7 @@ xmlXPathCompileExpr(xmlXPathParserContextPtr ctxt, int sort) {
     }
 
     if (xpctxt != NULL)
-        xpctxt->depth -= 1;
+        xpctxt->depth -= 10;
 }
 
 /**
